A new study has found that an all-day, extended-release stimulant fortreating attention-deficit hyperactivity disorder (ADHD) remainseffective for up to two years without significant side effects. In theOctober issue of the Journal of the American Association of Child &Adolescent Psychiatry, a multi-institutional research team reportsfinding that treatment with Concerta, a once-daily form of the drugmethylphenidate, successfully controlled ADHD symptoms in more than 200children with ADHD. The study was supported by McNeil Pharmaceuticals,which manufactures Concerta.
"Although ADHD is recognized as a chronic disease, we've known verylittle about the effects of chronic treatment," says Timothy Wilens,MD, of the Massachusetts General Hospital (MGH) PediatricPsychopharmacology Unit, lead author of the JAACAP report. "There havebeen concerns about whether the stimulant medications that are amainstay of treatment continue to be effective, whether patients buildup tolerance, or whether the drugs might have adverse effects oncardiovascular health or growth. This investigation sheds someimportant light on those questions."
The study initially enrolled more than 400 children, ages 6 to13, who previously had participated in short-term, placebo-controlledtrials of Concerta. In the new trial, all participants received theactive medication at one of three dose levels. Dosage could be adjustedto improve effectiveness or reduce side effects. Participants' heightand weight, blood pressure, heart rate and other clinical measures weretaken at regular intervals during the study period. The children'sparents and teachers were surveyed periodically regarding whether theybelieved treatment was effective in controlling ADHD symptoms
The entire, two-year study was completed by 229 participants, withothers dropping out for a variety of reasons. Throughout the studyperiod, measures of treatment effectiveness were consistent, witharound 85 percent of parents and teachers reporting treatment resultsto be good or excellent. However, it was necessary to increase thechildren's dose by about 25 percent during the study, with mostincreases happening during the first year. All the children grew atrates considered normal for their age, and they gained only slightlyless weight than would have been expected. In general, there were noclinically significant effects on blood pressure, heart rate, or othercardiac measures.
"We found these medications do continue to be effective in thelong-term. While some particicipants did need to increase dosage beyondwhat could be attributed to their growth, any tolerance that developedseemed to be slight and limited to the first year," says Wilens. "Wehaven't seen any clinically meaningful problems with height and weightor any cardiovascular difficulties in this study, which also is thefirst to evaluate this kind of daylong treatment in a large group ofchildren."
Wilens is an associate professor of Psychiatry at Harvard MedicalSchool. The study's co-authors are Keith McBurnett, PhD, University ofCalifornia at San Francisco; Mark Stein, PhD, University of Chicago;Marc Lerner, MD, University of California at Irvine; Thomas Spencer,MD, MGH; and Mark Wolraich, MD, University of Oklahoma.
Massachusetts General Hospital, established in 1811, is the originaland largest teaching hospital of Harvard Medical School. The MGHconducts the largest hospital-based research program in the UnitedStates, with an annual research budget of more than $450 million andmajor research centers in AIDS, cardiovascular research, cancer,cutaneous biology, medical imaging, neurodegenerative disorders,transplantation biology, stem cells and photomedicine. In 1994, MGH andBrigham and Women's Hospital joined to form Partners HealthCare System,an integrated health care delivery system comprising the two academicmedical centers, specialty and community hospitals, a network ofphysician groups, and nonacute and home health services.
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